scholarly journals Effect of Soil Application of AG3 Phosphonate on the Severity of Clubroot of Bok Choy and Cabbage Caused by Plasmodiophora brassicae

Plant Disease ◽  
2006 ◽  
Vol 90 (12) ◽  
pp. 1517-1522 ◽  
Author(s):  
P. A. Abbasi ◽  
G. Lazarovits
Keyword(s):  
Disease Severity ◽  
Brassica Rapa ◽  
Plasmodiophora Brassicae ◽  
Field Trials ◽  
Field Conditions ◽  
Infested Soil ◽  
Fresh Weight ◽  
Soil Application ◽  
Muck Soil

Field trials were carried out to test the effect of phosphonate fungicide (AG3) on the severity of clubroot of bok choy (Brassica rapa var. chinensis) and cabbage (B. rapa var. perkinensis and B. oleracea var. capitata) in commercial Ontario muck fields with a clubroot history. Disease severity also was examined in the same infested soil under greenhouse and microplot conditions. In microplot trials with bok choy, AG3 phosphonate concentrations of 0.07 and 0.14% a.i. applied before or after planting consistently reduced clubroot severity (1-to-4 rating) by 0.8 to 1.6 when planted in May or June. However, only the 0.14% a.i. preplanting treatment was effective in trials in July and August. Postplanting drenches of 0.14% a.i. were consistently effective throughout the season. Fresh weight of bok choy was increased or not affected by phosphonate treatments. Under field conditions, one (0.07, 0.14, and 0.21% a.i.) or two (0.07% a.i.) postplant-ing drench applications of phosphonate significantly reduced the incidence of clubroot by 52 to 87% and severity by 1.7 to 2.5 on bok choy in 2004 but not in 2005. In the 2004 trial, two applications of 0.07% a.i. AG3 phosphonate reduced the severity of clubroot comparably to single applications at 0.14 and 0.21% a.i. rates. Fresh weight of bok choy was increased by 34 to 86% with all phosphonate drench treatments in both years. With cabbage, AG3 postplanting drench treatments consistently reduced the severity of clubroot (1-to-5 rating) by a range of 0.7 to 3.3 under greenhouse, microplot, and field conditions. In the greenhouse, a single drench application of 0.07 and 0.14% a.i. AG3 phosphonate 1 day after transplanting cabbage seedlings to the infested muck soil reduced clubroot severity by 2.6 to 3.3 and increased fresh weight of cabbage tops by 66 to 69%. Similar results were seen with cabbage trials under both microplot and field conditions at all AG3 postplanting drench concentrations.

scholarly journals Effect of Host Resistance and Fungicide Application on Clubroot Pathotype 6 in Green Cabbage and Napa Cabbage

2012 ◽  
Vol 22 (3) ◽  
pp. 311-319 ◽  
Author(s):  
Catarina Saude ◽  
Alan McKeown ◽  
Bruce D. Gossen ◽  
Mary Ruth McDonald
Keyword(s):  
Brassica Oleracea ◽  
Brassica Rapa ◽  
Host Resistance ◽  
Plasmodiophora Brassicae ◽  
Field Trials ◽  
Organic Soils ◽  
Southern Ontario ◽  
Clubroot Resistance ◽  
Mineral Soils ◽  
Standard Cultivar

Field trials were conducted to evaluate resistance to clubroot (Plasmodiophora brassicae, pathotype 6) in green cabbage (Brassica oleracea var. capitata) and napa cabbage (Brassica rapa ssp. pekinensis) at sites in southern Ontario in 2009 and 2010. The reaction of green cabbage cultivars Kilaton, Tekila, Kilaxy, and Kilaherb and the commercial standard cultivars, Bronco or Atlantis, were evaluated on organic (two site-years) and mineral soils (two site-years) that were naturally infested with the clubroot pathogen. In addition, fluazinam fungicide was drench applied to one treatment of the commercial standard cultivar immediately after transplanting. The napa cabbage cultivars Yuki, Deneko, Bilko, and Mirako (in 2009) and Emiko, Mirako, Yuki, and China Gold (in 2010) were evaluated only on organic soils (two site-years). At harvest, the roots of each plant were assessed for clubroot incidence and severity. Also, plant and head characteristics of the resistant green cabbage cultivars were evaluated at one site in 2010. The green cabbage cultivars Kilaton, Tekila, Kilaxy, and Kilaherb were resistant to pathotype 6 (0% to 3.8% incidence), but ‘Bronco’ was susceptible (64% to 100% incidence). Application of fluazinam reduced clubroot severity on ‘Bronco’ by 6% at one of three sites. Resistance was more effective in reducing clubroot than application of fluazinam. Plant and head characteristics of the resistant cultivars were similar to those of ‘Bronco’ treated with fluazinam. Napa cabbage cultivars Yuki, Deneko, Bilko, Emiko, and China Gold were resistant to clubroot (0% to 13% incidence), and ‘Mirako’ was highly susceptible (87% to 92% incidence). We conclude that the clubroot resistance available in several cultivars of green and napa cabbage was effective against P. brassicae pathotype 6.

scholarly journals Liming and biofungicide for the control of clubroot in cauliflower1

2017 ◽  
Vol 47 (3) ◽  
pp. 303-311 ◽  
Author(s):  
Carlos Antônio dos Santos ◽  
Nelson Moura Brasil do Amaral Sobrinho ◽  
Evandro Silva Pereira Costa ◽  
Caio Soares Diniz ◽  
Margarida Goréte Ferreira do Carmo
Keyword(s):  
Root Growth ◽  
Field Experiment ◽  
Disease Severity ◽  
Plasmodiophora Brassicae ◽  
Dry Weight ◽  
Growth And Yield ◽  
Fresh Weight ◽  
Root Volume ◽  
Root Dry Weight ◽  
Significant Difference

ABSTRACT Clubroot, caused by Plasmodiophora brassicae, is a disease that limits the cauliflower cultivation and is difficult to control. This study aimed to evaluate the efficiency of liming combined with the use of Trichoderma harzianum-based biofungicide for the control of clubroot in cauliflower. In a field experiment, the use of the biofungicide in combination with the application of calcined limestone doses (0 Mg ha-1, 1.0 Mg ha-1, 2.0 Mg ha-1 and 4.0 Mg ha-1) was evaluated. Subsequently, in a greenhouse, the biofungicide combined with liming with quicklime (2.54 Mg ha-1) was tested, and cyazofamid and water were tested as controls. The disease severity and attributes related to root and plant development were analyzed. In the field experiment, the healthy root volume and fresh weight, total root dry weight and inflorescence fresh weight and diameter were all significantly increased, while the diseased root volume, in response to the limestone doses, was reduced. The biofungicide reduced the root growth and inflorescence fresh weight. In the greenhouse, liming increased the healthy root volume and fresh weight, as well as total root dry weight, and reduced the disease severity. No significant difference was observed between the biofungicide and the control (water), which were inferior to cyazofamid. The biofungicide was not efficient in controlling the disease and did not favour the growth of cauliflower plants, either alone or combined with liming. Liming reduced the disease severity and increased the cauliflower root growth and yield.

scholarly journals Interaction between Dickeya dianthicola and Pectobacterium parmentieri in Potato Infection under Field Conditions

2021 ◽  
Vol 9 (2) ◽  
pp. 316
Author(s):  
Tongling Ge ◽  
Fatemeh Ekbataniamiri ◽  
Steven B. Johnson ◽  
Robert P. Larkin ◽  
Jianjun Hao
Keyword(s):  
Disease Severity ◽  
Bacterial Species ◽  
Single Species ◽  
Soft Rot ◽  
Severity Index ◽  
Potato Production ◽  
Field Trials ◽  
Field Conditions ◽  
Bacterial Suspension ◽  
Potato Seed

Dickeya and Pectobacterium spp. both cause blackleg and soft rot of potato, which can be a yield-reducing factor to potato production. The purpose of this study was to examine the interaction between these two bacterial genera causing potato infection, and subsequent disease development and yield responses under field conditions. Analysis of 883 potato samples collected in Northeastern USA using polymerase chain reaction determined that Dickeya dianthicola and P. parmentieri were found in 38.1% and 53.3% of all samples, respectively, and that 20.6% of samples contained both D. dianthicola and P. parmentieri. To further investigate the relationship between the two bacterial species and their interaction, field trials were established. Potato seed pieces of “Russet Burbank”, “Lamoka”, and “Atlantic” were inoculated with bacterial suspension of D. dianthicola at 107 colony-forming unite (CFU)/mL using a vacuum infiltration method, air dried, and then planted in the field. Two-year results showed that there was a high correlation (p < 0.01) between yield loss and percent of inoculated seed pieces. In a secondary field trial conducted in 2018 and 2019, seed pieces of potato “Shepody”, “Lamoka” and “Atlantic” were inoculated with D. dianthicola, P. parmentieri, or mixture of both species, and then planted. In 2019, disease severity index, as measured by the most sensitive variety “Lamoka”, was 16.2 with D. dianthicola inoculation, 10.4 with P. parmentieri, 25.4 with inoculation with both bacteria. Two-year data had a similar trend. Thus, D. dianthicola was more virulent than P. parmentieri, but the co-inoculation of the two species resulted in increased disease severity compared to single-species inoculation with either pathogen.

scholarly journals Influence of Soil-Borne Inoculum of Plasmodiophora brassicae Measured by qPCR on Disease Severity of Clubroot-Resistant Cultivars of Winter Oilseed Rape (Brassica napus L.)

Pathogens ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 433
Author(s):  
Ann-Charlotte Wallenhammar ◽  
Zahra Saad Omer ◽  
Eva Edin ◽  
Anders Jonsson
Keyword(s):  
Disease Severity ◽  
Oilseed Rape ◽  
Plasmodiophora Brassicae ◽  
Severity Index ◽  
Field Trials ◽  
Substantial Variation ◽  
Winter Oilseed Rape ◽  
Brassica Napus L ◽  
Resistant Cultivars ◽  
Gene Copies

Use of resistant cultivars is considered the most effective tool in managing clubroot. Three clubroot-resistant commercial winter oilseed rape (OSR) cultivars and a susceptible ‘Cultivar mix’ were evaluated for disease severity index (DSI) and yield performance in field soils, selected for varying abundance of natural inoculum of Plasmodiophora brassicae. Seven field trials were carried out during 2017–2019 in winter OSR crops, and comparative bioassays were performed in a growth chamber. Substantial variation in clubroot infection between years was observed in the field trials. For Cultivar mix, a negative correlation (y = −252.3ln(x) + 58,897.6) was found between inoculum density and seed yield in five trials, whereas no correlation was found for the resistant cultivars. In bioassays, Cultivar mix exhibited a significantly high correlation between DSIb and number of gene copies g−1 soil (R2 = 0.72). For resistant cvs., Mentor and Alister, correlation was R2 = 0.45 and 0.58, respectively, indicating that resistance was under pressure. In field trials, DSIf of the resistant cultivars was lower (<27). The recommendation is thus to use clubroot-resistant cultivars of OSR as part of Integrated Pest Management in situations where abundance of P. brassicae DNA exceeds 1300 gene copies g−1 soil.

Effects of fungicide, seeding date and seedling age on clubroot severity, seedling emergence and yield of canola

2012 ◽  
Vol 92 (6) ◽  
pp. 1175-1186 ◽  
Author(s):  
S. F. Hwang ◽  
T. Cao ◽  
Q. Xiao ◽  
H. U. Ahmed ◽  
V. P. Manolii ◽  
...  
Keyword(s):  
Plant Height ◽  
Disease Severity ◽  
Sustainable Management ◽  
Plasmodiophora Brassicae ◽  
Seedling Emergence ◽  
Field Trials ◽  
Susceptible Cultivar ◽  
Clubroot Disease ◽  
Seedling Age ◽  
Seeding Date

Hwang, S. F., Cao, T., Xiao, Q., Ahmed, H. U., Manolii, V. P., Turnbull, G. D., Gossen, B. D., Peng, G. and Strelkov, S. E. 2012. Effects of fungicide, seeding date and seedling age on clubroot severity, seedling emergence and yield of canola. Can. J. Plant Sci. 92: 1175–1186. The infestation of seeds by Plasmodiophora brassicae can result in the transmission of clubroot disease in canola. Five fungicides, including Dynasty 100 FS (azoxystrobin), Helix Xtra (thiamethoxam+difenoconazole+metataxyl+fludioxonil), NebijinTM 5SC (flusulfamide), Prosper FX (clothianidin+carbathiin+trifloxystrobin+metalaxyl), and Vitavax RS (carbathiin+thiram), were evaluated under greenhouse conditions using artificially infested canola seeds for their efficacy in eliminating seed-borne inoculum. All of the fungicides significantly reduced clubroot relative to the non-treated control, but NebijinTM 5SC and Dynasty 100 FS were the most effective. However, in field trials with Cruiser 5 FS (thiamethoxam), Helix Xtra, Dynasty, Prosper and Sedaxane (pyrazole anilide) applied alone or as a mixture, none of the treatments reduced clubroot severity or improved seedling emergence or yield compared with the insecticidal control (Cruiser 5 FS) in the susceptible cultivar. Clubroot severity was lower in early-seeded canola compared with the late-seeded crops in 2 site-years. The younger seedlings had greater disease severity and reduced plant height and yield than did older seedlings in both resistant and susceptible canola cultivars. We conclude that a combination of approaches including seed treatments and manipulation of seeding dates in conjunction with deployment of resistant cultivars is necessary for the sustainable management of clubroot in canola.

scholarly journals Reaction to Plasmodiophora brassicae Pathotype 6 in Lines of Brassica Vegetables, Wisconsin Fast Plants, and Canola

HortScience ◽  
2012 ◽  
Vol 47 (3) ◽  
pp. 374-377 ◽  
Author(s):  
Kalpana K.C. Adhikari ◽  
Mary Ruth McDonald ◽  
Bruce D. Gossen
Keyword(s):  
Plasmodiophora Brassicae ◽  
Field Trials ◽  
Research Station ◽  
Infested Soil ◽  
Vegetable Crops ◽  
Selected Lines ◽  
Future Studies ◽  
Spring Canola ◽  
Brassica Vegetables ◽  
Short Season

Field trials were conducted from 2008 to 2010 to assess the disease reaction to clubroot, caused by Plasmodiophora brassicae Woronin, in selected lines of Brassica spp., including short-season vegetable crops [Shanghai pak choy (B. rapa subsp. Chinensis var. communis)], Chinese flowering cabbage (B. rapa subsp. Chinensis var. utilis), and napa cabbage (B. rapa subsp. Pekinensis), the Rapid Cycling Brassica Collection (RCBC), also known as Wisconsin Fast Plants, and spring canola (B. napus). The trials were conducted on naturally infested soil with P. brassicae at the Muck Crops Research Station in Ontario, Canada, where pathotype 6 is predominant. Clubroot incidence and severity were higher in 2008 and 2010 compared with 2009. The lines of Shanghai pak choy and Chinese flowering cabbage were highly susceptible to clubroot, but each of the clubroot-resistant cultivars of napa cabbage, ‘Deneko’, ‘Bilko’, and ‘Yuki’, was highly resistant to pathotype 6. Among the RCBC lines, B. carinata and B. juncea were highly susceptible and could be used as susceptible models for further studies. Two RCBC lines, B. napus and R. sativus, were resistant to pathotype 6. Two of the canola cultivars, 46A76 and 46A65, were susceptible, but two others, ‘45H21’ and ‘Invigor 5020LL’, were highly resistant to pathotype 6. This difference in response can be exploited in future studies of clubroot reaction in canola.

EVALUATION OF NONIONIC SURFACTANTS FOR CONTROL OF CLUBROOT OF CABBAGE USING BAREROOT AND PLUG TRANSPLANTS OF TWO CULTIVARS

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 607b-607
Author(s):  
W. Tietjen ◽  
P.J. Nitzsche ◽  
W.P. Cowgill ◽  
M.H. Maletta ◽  
S.A. Johnston
Keyword(s):  
Brassica Oleracea ◽  
Disease Severity ◽  
Nonionic Surfactants ◽  
Plasmodiophora Brassicae ◽  
Severity Index ◽  
Effective Control ◽  
Disease Severity Index

`Market Prize' and `Bravo' cabbage (Brassica oleracea Var. capitata L.), transplanted as peat plug and bareroot plants into a field naturally infested with Plasmodiophora brassicae, Woronin, were treated immediately after planting with a liquid or a granular surfactant. APSA 80™, applied in transplant water, significantly reduced percent clubbing and disease severity index (DSI) compared to control treatments. Miller Soil Surfactant Granular™ did not significantly reduce percent clubbing or DSI. There was a significant effect of cultivar on percent clubbing and DSI. There was no significant effect of transplant type on percent clubbing or DSI. This year's study culminates five years of investigation of surfactants for clubroot control. Specific surfactants have proven to be an effective control of clubroot in cabbage. Chemical names used: nonylphenoxypolyethoxyethanol (APSA 80™); alpha-alkanoic-hydro omega-hydroxy poly (oxyethylene) (Miller Soil Surfactant Granular™).

scholarly journals COR/LEA Proteins as Indicators of Frost Tolerance in Triticeae: A Comparison of Controlled versus Field Conditions

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 789
Author(s):  
Klára Kosová ◽  
Miroslav Klíma ◽  
Ilja Tom Prášil ◽  
Pavel Vítámvás
Keyword(s):  
Cold Acclimation ◽  
Field Experiments ◽  
Quantitative Relationship ◽  
Field Trials ◽  
Frost Tolerance ◽  
Late Embryogenesis Abundant ◽  
Field Conditions ◽  
Lea Proteins ◽  
Winter Cereals ◽  
Vernalisation Requirement

Low temperatures in the autumn induce enhanced expression/relative accumulation of several cold-inducible transcripts/proteins with protective functions from Late-embryogenesis-abundant (LEA) superfamily including dehydrins. Several studies dealing with plants grown under controlled conditions revealed a correlation (significant quantitative relationship) between dehydrin transcript/protein relative accumulation and plant frost tolerance. However, to apply these results in breeding, field experiments are necessary. The aim of the review is to provide a summary of the studies dealing with the relationships between plant acquired frost tolerance and COR/LEA transcripts/proteins relative accumulation in cereals grown in controlled and field conditions. The impacts of cold acclimation and vernalisation processes on the ability of winter-type Triticeae to accumulate COR/LEA proteins are discussed. The factors determining dehydrin relative accumulation under controlled cold acclimation treatments versus field trials during winter seasons are discussed. In conclusion, it can be stated that dehydrins could be used as suitable indicators of winter survival in field-grown winter cereals but only in plant prior to the fulfilment of vernalisation requirement.

scholarly journals Epidemiology and management of bacterial leaf spot on watermelon caused byPseudomonas syringae

Plant Disease ◽  
2017 ◽  
Vol 101 (7) ◽  
pp. 1222-1229 ◽  
Author(s):  
E. A. Newberry ◽  
L. Ritchie ◽  
B. Babu ◽  
T. Sanchez ◽  
K. A. Beckham ◽  
...  
Keyword(s):  
Disease Severity ◽  
Pseudomonas Syringae ◽  
Leaf Spot ◽  
Negative Relationship ◽  
Disease Outbreaks ◽  
Field Trials ◽  
Multiple Regression Model ◽  
Bacterial Leaf Spot ◽  
Progress Curve ◽  
Cool Conditions

Bacterial leaf spot of watermelon caused by Pseudomonas syringae has been an emerging disease in the southeastern United States in recent years. Disease outbreaks in Florida were widespread from 2013 to 2014 and resulted in foliar blighting at the early stages of the crop and transplant losses. We conducted a series of field trials at two locations over the course of two years to examine the chemical control options that may be effective in management of this disease, and to investigate the environmental conditions conducive for bacterial leaf spot development. Weekly applications of acibenzolar-S-methyl (ASM) foliar, ASM drip, or copper hydroxide mixed with ethylene bis-dithiocarbamate were effective in reducing the standardized area under the disease progress curve (P < 0.05). Pearson’s correlation test demonstrated a negative relationship between the average weekly temperature and disease severity (–0.77, P = 0.0002). When incorporated into a multiple regression model with the square root transformed average weekly rainfall, these two variables accounted for 71% of the variability observed in the weekly disease severity (P < 0.0001). This information should be considered when choosing the planting date for watermelon seedlings as the cool conditions often encountered early in the spring season are conducive for bacterial leaf spot development.

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